1. Field of The Invention
The present invention relates to a medal cleaning apparatus for mixing, jumbling and then cleaning medals for use in, for example, slot machines etc.
2. Description of The Related Art
This kind of medal cleaning apparatus is disclosed in, for example, Japanese Patent Laid-Open Publication Hei. 3-242186. Here, the apparatus is constructed from a pipe, a spiral member installed within the pipe, a driving mechanism for rotating the spiral member and a filter set-up on the outside of the upper end of the pipe. In this apparatus, medals are introduced together with cleaning material at the lower end of the pipe and the spiral member is rotated. The medals and the cleaning material are then mixed and jumbled together and the medals are cleaned by coming into contact with the cleaning material. The medals and the cleaning material are transported in the direction of the upper end of the pipe as they are jumbled together by the spiral member and are then expelled from the upper end of the pipe. The expelled medals and cleaning material are then separated by the filter, with the cleaning materials separated by the filter being used again.
A pachinko ball cleaning apparatus similar to the aforementioned medal cleaning apparatus is disclosed in Japanese Utility Model Laid-Open Publication Hei. 2-149285. In this apparatus, metal pachinko balls and cleaning material are mixed and jumbled together by a pipe and spiral member before being separated from each other by a filter.
In these cleaning apparatus, the upper end of the pipe has been cut horizontally, although this kind of structure did not present a problem for the pachinko ball cleaning apparatus. However, in the case of the medal cleaning apparatus, a problem occurred where the medals were not expelled smoothly. Research by the applicant for the present invention revealed that medals were becoming stuck in the expulsion portion at the upper end of the pipe. Therefore, it is a problem that the stuck medals must be removed by hand every time the trouble occurs. Investigations carried out by the applicant with regards to this were as follows.
First, the filter was inclined with respect to the circumference of the upper end of the pipe so as to make it easy for the medals to slip off. i.e. the surface of the filter was inclined with respect to the plane of the opening at the upper end of the pipe. A step difference therefore occurred between one side of the upper end of the pipe and the filter. On the other hand, however, the medals were ejected from the upper end of the pipe as a result of being pushed by the spiral member. The falling speed of the medals at the time of ejection was therefore almost zero or in the region of zero. As a result of this, depending on the position of the medals at the time of expulsion, the medals were observed to become held-up as a result of leaning against the side wall of the pipe protruding at the step difference portion. Also, the medals were expelled at the plane of the opening for the pipe radially as a result of the pushing action of the spiral body. This means that medals were also expelled from the rear of the pipe, i.e. the opposite side of the pipe from which it was intended to expel the medals from. This therefore served as a hindrance at the upper end of the pipe and it was at this portion at which hold-ups occurred.